RESUMEN
A procedure for the simultaneous quantitative determination and selective identification of potassium canrenoate and butizide is proposed. The amount of canrenone, the degradation product of potassium canrenoate, is also determined. Elution of these compounds is investigated on LiChrosorb RP-18 and RP-8 columns. The analysis time was shorter on a RP-8 column while the specific identification was still possible. Therefore, the LiChrosorb RP-8 column was chosen. The eluent consisted of an acetonitrile--0.05 M phosphate buffer, pH 4 (45:55) mixture. Quantitative determination was performed at the absorption maximum of each compound: 286 nm for potassium canrenoate and for canrenone, 271 nm for butizide. This change in wavelength is performed automatically by the computer that controls the spectrophotometric diode array detector.
Asunto(s)
Ácido Canrenoico/análisis , Canrenona/análisis , Hidroclorotiazida/análogos & derivados , Pregnadienos/análisis , Inhibidores de los Simportadores del Cloruro de Sodio/análisis , Cromatografía Líquida de Alta Presión , Diuréticos , Estabilidad de Medicamentos , Hidroclorotiazida/análisis , Indicadores y Reactivos , Espectrofotometría Ultravioleta , ComprimidosRESUMEN
This paper deals with the specific identification of several thiazide, potassium-sparing and loop diuretics. The liquid chromatographic behaviour of these compounds is studied. Different organic modifiers (methanol, acetonitrile and tetrahydrofuran) are compared in terms of selectivity for the thiazide diuretics. An acetonitrile-water (40:60) eluent can be used to identify the thiazide diuretics. The loop and potassium-sparing diuretics are well chromatographed at an acidic pH in the presence of propylamine hydrochloride. This study enables us to select the right mobile phase composition for any given selectivity or resolution. The determination of the dead volume in different chromatographic systems is also discussed. A mixture of organic solvent and deuterium oxide in the same volume ratio as the eluent is used as dead volume marker. The signal is monitored with a UV detector at low wavelength.